refactor(db): remove unnecessary created_at column from perm whitelist query

The `created_at` field is no longer needed in the result set,
so it was removed from the SELECT query to reduce data transfer
and simplify the response.

db.go

@@ -191,7 +191,7 @@ func ListTempEntries(db *sql.DB) ([]map[string]interface{}, error) {
 }
 
 func ListPermEntries(db *sql.DB) ([]map[string]interface{}, error) {
-	rows, err := db.Query(`SELECT entry, created_at FROM perm_whitelist ORDER BY created_at `)
+	rows, err := db.Query(`SELECT entry FROM perm_whitelist ORDER BY created_at`)
 	if err != nil {
 		return nil, err
 	}